Bushings are typically installed at the end of an electrical conduit, including electrical metallic tubing (EMT) and rigid conduit. Bushings are installed at the end of such EMT or conduit to prevent electrical conductors within the EMT or conduit from chafing in the region where the conductors exit the tubing or conduit.
Grounding bushings are used so that the EMT or conduit may be grounded or provided with a path to ground as required by various electrical codes.
It is known in the industry that various trade sizes for EMT and rigid conduit ostensibly having the same outer diameter (OD) may nevertheless have significant variations in the OD especially between EMT and rigid conduit having the same trade size, particularly for trade sizes of two inches and below. Such EMT and rigid conduit are used in various electrical installations, including in solar panel applications, where the conductors are typically low voltage conductors associated with such solar panels. Various electrical codes require that the EMT or rigid conduit maintain proper grounding and therefore there is a need for grounding bushings to meet the code requirements for such installations.
Because of the trade size variation in OD between EMT and rigid conduit, there has been a need for a grounding bushing which can accommodate the variation in the OD for EMT and rigid conduit for the same trade size.